change ConstEvaluatable to use ty::Const

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -161,11 +161,20 @@ pub fn try_unify_abstract_consts<'tcx>(
 #[instrument(skip(infcx), level = "debug")]
 pub fn is_const_evaluatable<'tcx>(
     infcx: &InferCtxt<'tcx>,
-    uv: ty::UnevaluatedConst<'tcx>,
+    ct: ty::Const<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     span: Span,
 ) -> Result<(), NotConstEvaluatable> {
     let tcx = infcx.tcx;
+    let uv = match ct.kind() {
+        ty::ConstKind::Unevaluated(uv) => uv,
+        ty::ConstKind::Param(_)
+        | ty::ConstKind::Bound(_, _)
+        | ty::ConstKind::Placeholder(_)
+        | ty::ConstKind::Value(_)
+        | ty::ConstKind::Error(_) => return Ok(()),
+        ty::ConstKind::Infer(_) => return Err(NotConstEvaluatable::MentionsInfer),
+    };
 
     if tcx.features().generic_const_exprs {
         if let Some(ct) = AbstractConst::new(tcx, uv)? {
@@ -285,7 +294,7 @@ fn satisfied_from_param_env<'tcx>(
     for pred in param_env.caller_bounds() {
         match pred.kind().skip_binder() {
             ty::PredicateKind::ConstEvaluatable(uv) => {
-                if let Some(b_ct) = AbstractConst::new(tcx, uv)? {
+                if let Some(b_ct) = AbstractConst::from_const(tcx, uv)? {
                     let const_unify_ctxt = ConstUnifyCtxt { tcx, param_env };
 
                     // Try to unify with each subtree in the AbstractConst to allow for

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1304,7 +1304,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
 
                 match obligation.predicate.kind().skip_binder() {
-                    ty::PredicateKind::ConstEvaluatable(uv) => {
+                    ty::PredicateKind::ConstEvaluatable(ct) => {
+                        let ty::ConstKind::Unevaluated(uv) = ct.kind() else {
+                            bug!("const evaluatable failed for non-unevaluated const `{ct:?}`");
+                        };
                         let mut err =
                             self.tcx.sess.struct_span_err(span, "unconstrained generic constant");
                         let const_span = self.tcx.def_span(uv.def.did);
@@ -2368,7 +2371,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 if predicate.references_error() || self.is_tainted_by_errors() {
                     return;
                 }
-                let subst = data.substs.iter().find(|g| g.has_non_region_infer());
+                let subst = data.walk().find(|g| g.is_non_region_infer());
                 if let Some(subst) = subst {
                     let err = self.emit_inference_failure_err(
                         body_id,

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -476,9 +476,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                         Err(NotConstEvaluatable::MentionsInfer) => {
                             pending_obligation.stalled_on.clear();
                             pending_obligation.stalled_on.extend(
-                                uv.substs
-                                    .iter()
-                                    .filter_map(TyOrConstInferVar::maybe_from_generic_arg),
+                                uv.walk().filter_map(TyOrConstInferVar::maybe_from_generic_arg),
                             );
                             ProcessResult::Unchanged
                         }

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -148,13 +148,8 @@ pub fn predicate_obligations<'tcx>(
             wf.compute(a.into());
             wf.compute(b.into());
         }
-        ty::PredicateKind::ConstEvaluatable(uv) => {
-            let obligations = wf.nominal_obligations(uv.def.did, uv.substs);
-            wf.out.extend(obligations);
-
-            for arg in uv.substs.iter() {
-                wf.compute(arg);
-            }
+        ty::PredicateKind::ConstEvaluatable(ct) => {
+            wf.compute(ct.into());
         }
         ty::PredicateKind::ConstEquate(c1, c2) => {
             wf.compute(c1.into());
@@ -476,14 +471,14 @@ impl<'tcx> WfPredicates<'tcx> {
                 // obligations are handled by the parent (e.g. `ty::Ref`).
                 GenericArgKind::Lifetime(_) => continue,
 
-                GenericArgKind::Const(constant) => {
-                    match constant.kind() {
+                GenericArgKind::Const(ct) => {
+                    match ct.kind() {
                         ty::ConstKind::Unevaluated(uv) => {
                             let obligations = self.nominal_obligations(uv.def.did, uv.substs);
                             self.out.extend(obligations);
 
                             let predicate =
-                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv))
+                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct))
                                     .to_predicate(self.tcx());
                             let cause = self.cause(traits::WellFormed(None));
                             self.out.push(traits::Obligation::with_depth(
@@ -500,7 +495,7 @@ impl<'tcx> WfPredicates<'tcx> {
                                 cause,
                                 self.recursion_depth,
                                 self.param_env,
-                                ty::Binder::dummy(ty::PredicateKind::WellFormed(constant.into()))
+                                ty::Binder::dummy(ty::PredicateKind::WellFormed(ct.into()))
                                     .to_predicate(self.tcx()),
                             ));
                         }